Composite Permanent Magnet

ABSTRACT

A hard disk drive includes composite magnet as voice coil motor magnet, where a composite permanent magnet comprising: a first magnet (M1), a second magnet (M2) and a third magnet (M3). M1, M2 and M3 are deposited, bonded, sintered, glued or assembled together and next to each other. The directions of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 is substantially perpendicular to the direction of saturation magnetization of M1 and M3.

FIELD OF THE INVENTION

The present disclosure relates to a novel permanent magnet technology and its use in high efficiency voice coil motors (VCM), particular for the application utilized in hard disk drive.

BACKGROUND OF THE INVENTION

Permanent magnets (PM) create their own persistent magnetic fields and are typically used in electromagnetic induction devices such as motors and generators. Permanent magnets are made from a magnetic material such as ferrite. Additional magnetic materials from rare earth metals, such as Samarium-Cobalt (SmCo), or Neodymium-Iron-Boron (NdFeB) have also been used. While an NdFeB magnet is stronger (e.g., according to maximum energy product (BH)max than an SmCo magnet which is stronger than ferrite, it becomes difficult to increase the magnetic strength even further and Neodymium magnets are much more expensive than ferrite due to the scarcity of Neodymium.

Moreover, a magnet is typically strongest at the surface of the magnet. The magnetization at the magnet surface then decreases with distance from the magnet surface due to a large self-demagnetization field generated by surface magnetic charges, thereby reducing the strength of the magnet away from the surface, such that the magnetic flux density decreases with distance from the magnet. Other various magnetic properties such as magnetic anisotropy, magnetic moment and thus magnetic flux density, etc. may decline as the operating temperature increases. Additionally, there are several grades of NdFeB, SmCo, ferrite, etc. magnets, where higher grades indicate stronger magnets. However, the cost of the magnet may increase in proportion with the grade. The torque generated in an electromagnetic induction device, such as a motor is proportional to the magnetic flux density produced by a permanent magnet in the stator. As the magnetic flux density increases, the efficiency of the motor increases. For the case of hard disk drive, permanent magnets are utilized in the motors to rotate magnetic disks and the head stack assembly that host the magnetic recording heads to perform read and write operations. A higher magnetic field gradient provided by the permanent magnet will lead to an increased efficiency for drive random access operation or a reduced power consumption.

SUMMARY OF THE INVENTION

The presently disclosed embodiments address many of the issues described above with respect to permanent magnets. The permanent magnets described herein address these disadvantages, having a high magnetic flux density, thereby increasing the efficiencies of motors and generators that implement the permanent magnets. The embodiments disclosed herein are suitable for use in hard disk drive VCM in which permanent magnets are presently employed.

In an embodiment, a composite permanent magnet comprises a first magnet (M1), a second magnet (M2) and a third magnet (M3). M1, M2 and M3 are deposited, bonded, glued or assembled together and next to each other. The directions of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 is substantially perpendicular to the direction of saturation magnetization of M1 and M3. Further in an embodiment, the composite permanent magnet is attached to a soft magnetic yoke. In practice, the soft magnetic yoke can be a flat piece or a flat plate with in a predefined shape. The soft magnetic yoke may further include mounting holes.

In another embodiment, a composite permanent magnet comprising: a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). M1, M2, M3, M4 and M5 are deposited or assembled together and next to each other. The directions of the saturation magnetization of M2 and M4 are opposite to each other. The direction of the saturation magnetization of M1 and M5 is substantially antiparallel to the direction of the saturation magnetization of M3. The directions of saturation magnetization of M1, M3 and M5 are substantially perpendicular to the direction of saturation magnetization of M2 and M4.

Moreover, the width of M1, M3 and M5 may be ⅓ of the width of M2 and M4, the length and the height of M1, M2, M3, M4 and M5 are approximately the same.

Furthermore, each of the magnetic material may be a ferrite (such as Barium-Iron-Oxygen (Ba—Fe—O), Barium-Nickel-Iron-Oxygen (Ba—Ni—Fe—O), Barium-Strontium-Nickel-Iron-Oxygen (Ba—Sr—Ni—Fe—O), etc.), alnico (such as Aluminum-Nickel-Cobalt (Al—Ni—Co), Aluminum-Nickel-Cobalt-Iron (Al—Ni—Co—Fe), Aluminum-Nickel-Cobalt-Iron-Copper (Al—Ni—Co—Fe—Cu), etc.), rare earth-transition metal-based permanent magnetic materials X-Y or X-Y-Z (where X includes rare-earth elements and their combinations, such as Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Neodymium-Dysprosium (NdDy), Neodymium-Dysprosium-Terbium-Gadolinium (NdDyTbGd) and Neodymium-Dysprosium-Terbium (NdDyTb), etc.; Y includes transition metal elements and/or their combinations, such as Iron (Fe), Cobalt (Co), Manganese (Mn), Nickel (Ni), Iron-Cobalt (FeCo), Iron-Cobalt-Nickel (FeCoNi), Iron-Cobalt-Nickel-Manganese (FeCoNiMn), etc.; and Z includes non-metal elements and/or other doping elements and their combinations, such as Boron (B), Silicon (Si), Carbon (C), Nitrogen (N), Copper (Cu), Silver (Ag), Zirconium (Zr), etc.), Mn-based permanent magnetic materials X-Y or X-Y-Z (where X includes Mn, Fe, Manganese-Iron (MnFe), etc.; and Y includes Bismuth (Bi), Al, Gallium (Ga), and/or other doping elements such as Praseodymium (Pr), as well as the combination of these elements), transition metal-platinum-based magnetic material X-Y (where X includes transition metal elements and/or their combinations, such as Fe, Co, FeCo, etc.; and Y includes Platinum (Pt), Rhodium (Rh), Palladium (Pd), Zr, and/or their combinations with/without other doping elements), or Iron-Nitride (Fe—N). Specifically, each of the magnets can be Neodymium-Iron-Boron (NdFeB) based materials with different percentage of Neodymium (Nd) concentration.

In another embodiment, a composite permanent magnet comprising: a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4), a fifth magnet (M5) and a sixth magnet (M6). M1, M2, M3, M4, M5 and M6 are deposited or assembled together and next to each other. The directions of the saturation magnetization of M2 and M5 are opposite to each other. The direction of the saturation magnetization of M1, M3, M4 and M5 are not along the direction of the saturation magnetization of either M2 or M4.

Each of the above magnet material may be any of the above-mentioned magnetic materials. In an embodiment, each magnet utilized in the composite magnet are the same type of materials. In another embodiment, the materials for M1 and M3 use different materials from M2 for the composite permanent magnet with M1, M2 and M3. In another embodiment, the materials for M1, M3 and M5 use different materials from M2 and M4 for the composite permanent magnet with M1, M2, M3, M4 and M5.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages described herein will become more fully understood from the detailed description and the accompanying drawings and tables. The drawings constitute a part of this specification and include exemplary embodiments of the invention, which may be embodied in various forms. It is to be understood that in some instances, various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention; therefore, the drawings are not necessarily to scale. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to the conceptual design or structural elements represent each particular component or element of the apparatus.

FIG. 1A illustrates a conventional magnet utilized in a hard disk drive voice coil motor;

FIG. 1B illustrates magnet design configuration utilized in typical hard disk drive voice coil motor;

FIG. 1C illustrates a side view of the device operation with conventional magnet and accessory components in a hard disk drive voice coil motor;

FIG. 1D illustrates a perspective view of the magnet utilized in conventional hard disk drive voice coil motor;

FIG. 2 illustrates an example structure of a composite permanent magnet as described in an embodiment of the invention;

FIG. 3 illustrates a detailed magnetization and materials configuration utilized for a composite magnet as described in an embodiment;

FIG. 4 illustrates an example of the composite permanent magnets with accessory components that perform device operation in a hard disk drive voice coil motor;

FIG. 5 illustrates the relative magnetic flux spatial distribution from the composite magnet as described in an embodiment vs. conventional magnet;

FIG. 6 illustrates another embodiment of the proposed composite magnet;

FIG. 7 illustrates a perspective view of another embodiment of the proposed composite magnet;

FIG. 8 illustrates another embodiment of the proposed composite magnet;

FIG. 9 illustrates a perspective view of one of the embodiments of the proposed composite magnet;

FIG. 10 illustrates a perspective view of another embodiment of the proposed composite magnet;

FIG. 11A illustrates an example structure of a composite permanent magnet as described in another embodiment of the invention;

FIG. 11B is the front top view of the composite permanent magnet design as described in another embodiment of the invention;

FIG. 11C is the perspective view of the composite permanent magnet design as described in another embodiment of the invention;

FIG. 11D is the front top view of the composite permanent magnet placed on soft magnetic yoke as described in another embodiment of the invention;

FIG. 11E is the front top view of the composite permanent magnet placed on soft magnetic yoke as described in another embodiment of the invention;

FIG. 12A illustrates an example structure of a composite permanent magnet as described in another embodiment of the invention;

FIG. 12B illustrates an example structure of a composite permanent magnet as described in another embodiment of the invention;

FIG. 12C is the front top view of the composite permanent magnet design as described in another embodiment of the invention;

FIG. 12D is the perspective view of the composite permanent magnet design as described in another embodiment of the invention;

FIG. 13A is the front top view of the composite permanent magnet design as described in another embodiment of the invention;

FIG. 13B is the perspective view of the composite permanent magnet design as described in another embodiment of the invention;

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, numerous specific details are disclosed to provide a thorough understanding of embodiments of the method, system and apparatus. One skilled in the relevant art will recognize, however, that embodiments of the method, system and apparatus described herein may be practiced without one or more of the specific details, or with other electronic devices, methods, components, and materials, and that various changes and modifications can be made while remaining within the scope of the appended claims. In other instances, well-known electronic devices, components, structures, materials, operations, methods, process steps and the like may not be shown or described in detail to avoid obscuring aspects of the embodiments. Embodiments of the apparatus, method and system are described herein with reference to figures.

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, electronic device, method or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may refer to separate embodiments or may all refer to the same embodiment. Furthermore, the described features, structures, methods, electronic devices, or characteristics may be combined in any suitable manner in one or more embodiments.

As illustrated in FIG. 1A, a sub-set of the magnet component, and other component utilized in a hard disk drive is shown. The soft magnetic yoke 139 a is directly connected with the permanent magnet 138, and another soft magnetic yoke 139 b is fixed at the bottom with the hard disk drive case (not shown here). Thus, a magnetic field flux closure path is established between permanent magnet 138 and soft magnetic yoke 139 a. The current (i) flows through the voice coil motor (VCM) coil 137 within the magnetic field generated by the magnet 138. Accordingly, thrust is applied to the VCM coil 137. By changing the direction of the current, the thrust direction can be changed and thus lead to rotation of the swing arm 132 that connected with the recording head assembly not shown here) and the VCM coil 137. The permanent magnet 138 utilized in this structure has two pieces, with magnetization directions to be opposite to each other. This permanent magnet 138 and the soft magnetic yoke 139 b together is called VCM magnet. In each hard disk drive, two pieces VCM magnets are utilized.

As illustrated in FIG. 1B. The magnetization directions of the permanent magnet 138 a and 138 b utilized in a hard disk drive are shown as the arrows. This approach will create a spatially changed magnetic field outside the permanent magnet 138 a and 138 b. In practice, the permanent magnets 138 a and 138 b are attached to the yoke 139 a. Another magnet yoke 139 b also have the permanent magnet 138 a′ and 139 b′, with the same structure but attached to the opposite side of the yoke 139 b′. This will generate thrust when a current coil placed between the yoke 139 a and yoke 139 b. The torque generated is proportional to the field gradient within the space. The higher the peak magnetic field with a given confined space, usually the higher torque generated for a given VCM (not shown here), which will translate, into a higher rotation speed, or a lower energy consumption. By adding two pieces of permanent magnets 138 a and 138 b with magnetization opposite to each other, spatial field gradient can be created.

FIG. 1C illustrate a side view of the baseline structure and the magnetic field distribution for the conventional approach. The yoke 139 a and 139 b are using soft magnetic materials. The magnet 138 a and 138 b are made of permanent magnet with magnetization in opposite directions. With the magnetization direction illustrated in FIG. 1C. The magnet 138 a and 138 b are attached to the soft magnetic materials 139 a. The magnet 138 a′ and 138 b′ are made of permanent magnet with magnetization in opposite directions. With the magnetization direction illustrated in FIG. 1C. The magnet 138 a′ and 138 b′ are attached to the soft magnetic materials 139 b. As the VCM coil 137 generates current (i), the thrust will be added which will cause rotation of the head stack assembly (not shown here).

FIG. 1D illustrates a perspective view of the magnet 10 utilized in conventional hard disk drive voice coil motor. The magnetization direction of the permanent magnet utilized in a hard disk drive is shown by the arrows. This approach will create a spatially changed magnetic field outside the permanent magnets. The permanent magnet includes two pieces, 138 a and 138 b with magnetization direction opposite to each other. The soft magnet 139 a is attached to one side of the permanent magnet. The letter N and S represent the magnetic south pole and magnetic north pole from each individual permanent magnet piece. The arrow direction represents magnetization direction of each piece of the permanent magnet. The magnet may further be coated with metallic layer. In this particular example, the Ni coat is platted to the permanent magnet 138 a, 138 b and the soft magnetic yoke 139 a, in practice, the soft magnetic yoke 139 a includes mounting 145 to allow the whole apparatus to be secured attach to the hard disk drive.

FIG. 2 illustrates an example structure of a composite permanent magnet as described in an embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1), the third magnet (M3) and the fifth magnet (M5) has magnetization direction substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). In addition, the third magnet (M3) has magnetization direction to be opposite with the magnetization direction of the first magnet (M1) and the fifth magnet (M5). Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 3 illustrates a detailed magnetization and materials configuration utilized for a composite magnet as described in an embodiment as shown in FIG. 2. Each piece of the permanent magnet utilized in the composite magnet is shown separately. The side view of each piece of the materials is shown. Thus, the length of the materials is not shown. In most applications, the length of the materials (the dimension goes into the plane) for M1, M2, M3, M4 and M5 are approximately the same. The width of M1, M2, M3, M4 and M5 are W1, W2, W3, W4 and W5 respectively. The height of M1, M2, M3, M4 and M5 are H1, H2, H3, H4 and H5 respectively. In one embodiment, the width of M2 and M4 is approximately the same, and the width of M2 and M4 is larger than the width of M1, M3 and M5 respectively, i.e. W2=W4>W1=W3=W5 or W2≅W4>W1≅W3≅W5. The width of M1, M3 and M5 can be approximately the same. The height of M1, M2, M3, M4 and M5 is typically the same. N represent magnetization north pole and S represent magnetization south pole. The magnetization direction of M2 and M4 are along the height direction, and the magnetization direction of M1, M3 and M5 are along the width direction. The composite magnet can be bonded, or glued or pressed together, acting as one piece. The composite structure for a finished permanent magnet is shown in FIG. 2.

FIG. 4 illustrates example structures of composite permanent magnets with accessory components that perform device operation in a hard disk drive using a voice coil motor (VCM). With the composite magnet, the flux shunting path will be different. The surface magnetization of M2 and M4 will have less leakage as compared to conventional approach. More magnetic flux will enter from permanent magnet M2 b and M4 to the permanent magnet M2 and M4 b respectively. The calculated magnetic field and field gradient in the gap region where the VCM coil 137 located, is higher for composite magnets as compared to conventional magnets. The peak field measured at the location of VCM coil 137 during operation for this approach can be more than 20% higher than conventional magnet design as utilized in FIG. 1. This enhancement will translate into higher VCM operation efficiency, which will lead to higher access speed or lower power consumption.

FIG. 5 illustrates the relative magnetic field or magnetic flux spatial distribution from one of the composite magnet solutions as described in this disclosure vs. conventional magnet. The baseline is for conventional magnet, the composite magnet is from one of the embodiments of the proposed solution. The total size (and weight) and the choice of materials of the magnets for both cases are chosen to be the same. In this particular example, the composite magnet provide additional 20% magnetic field and magnetic field gradient, which will translate to an improved efficiency or a 20% lower energy consumption in HDD operation if keep the seek time to be the same. Since seeking operation is one of the steps that consumes the most energy in drive operation, this solution will help to reduce drive energy consumption significantly.

In addition, when there are more platters added to each unit of hard disk drive, the total head stack assembly have an increased weight. Therefore, a stronger magnetic field and field gradient will help to overcome the penalty due to weight increase, and help to maintain efficiency of the operation, which reflect to an improved (reduced) seek time. In either approach, one other advantage of the composite magnet is to enable a faster rotation speed due to efficiency change. This will help to increase the hard disk drive number of read and write operations per second (R/Wops), which is a crucial performance metric. By optimizing the size of each magnet utilized in the composite magnet, the operation efficiency can be increased by more than 20%. Since the latency is the top contributor for random access input/output operations per second (iops), increase the magnet flux that can be utilized to drive head stack for the recording head will help to maintain or increase iops capability, reduce the seek time as compare to conventional approach.

FIG. 6 illustrates another embodiment of the proposed composite permanent magnet. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). In another embodiment, the composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 7 illustrates a perspective view of the embodiment of the proposed composite permanent magnet as described in FIG. 6. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the width to be approximately same to each other. The height of the first magnet (M1), the second magnet (M2) and the third magnet (M3) is approximately the same. The width of the second magnet (M2) is smaller than the first and the third magnets (M1 and M3).

FIG. 8 illustrates another embodiment of the proposed composite permanent magnet. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3) and a fourth magnet (M4). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). In another embodiment, the composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 9 illustrates a perspective view of one of the embodiments of the proposed composite permanent magnet to be utilized in hard disk drive. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the width to be approximately same to each other. The height of the first magnet (M1), the second magnet (M2) and the third magnet (M3) is approximately the same. The width of the second magnet (M2) is approximately the same or smaller than the first and the third magnets (M1 and M3). The letter N and S represent the magnetic north and magnetic south pole. The dashed arrow illustrate the magnetization direction in each piece of the magnet. The composite magnet with each piece (M1, M2 and M3) are attached to the soft magnetic yoke 139 a. Both the composite magnet and the soft magnetic yoke 139 a are wrapped by metallic coat.

FIG. 10 illustrates a perspective view of another embodiment of the proposed composite permanent magnet to be utilized in hard disk drive. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1), the third magnet (M3) and the fifth magnet (M5) has magnetization direction substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). In addition, the third magnet (M3) has magnetization direction to be opposite with the magnetization direction of the first magnet (M1) and the fifth magnet (M5). The dashed arrow shows the magnetization direction within each magnet. The composite magnet is attached to the soft magnetic yoke 139 a. Both the composite magnet and the soft magnetic yoke 139 a are wrapped by metallic coat.

The width of M1, M2, M3, M4 and M5 are W1, W2, W3, W4 and W5 respectively. The height of M1, M2, M3, M4 and M5 are H1, H2, H3, H4 and H5 respectively. In one embodiment, the width of M2 and M4 is approximately the same, and the width of M2 and M4 is larger than the width of M1, M3 and M5 respectively, i.e. W2=W4>W1=W3=W5 or W2≅W4>W1≅W3≅W5. The width of M1, M3 and M5 can be approximately the same. The height of M1, M2, M3, M4 and M5 is typically the same. The magnetization direction of M2 and M4 are along the height direction, and the magnetization direction of M1, M3 and M5 are along the width direction. The composite magnet can be bonded, or glued or pressed together, acting as one piece. The letter N and S represent the magnetic north and magnetic south pole. The dashed arrow illustrate the magnetization direction in each piece of the magnet. Each piece of magnet M1, M2, M3, M4 and M5 in the composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 11A illustrates an example structure of a composite permanent magnet as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). The dashed arrows shows the magnetization direction within each magnet. N and S represents magnetic north and south pole. The shape of the magnet (M1, M2 and/or M3) as viewed from the side view is in trapezoid shape, with corners are not equal to 90 degrees. This approach enables further optimization of the magnetic surface charge to improve magnetic flux or magnetic field distribution that can be utilized by the VCM coil, which improves operation efficiency. In another embodiment, the composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 11B is the front top view of the composite permanent magnet design as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). The shape of the magnet (M1, M2 and/or M3) as viewed from the side view is in trapezoid shape, with corners are not equal to 90 degrees. The magnetic charges on the magnet surface, such as S1 and S2 also contribute to the field as measured outside the composite magnet. This approach enables further optimization of the magnetic surface charges to improve magnetic flux or magnetic field distribution that can be utilized by the VCM coil, which improves operation efficiency. In another embodiment, the composite magnet is attached to the soft magnetic yoke (not shown here).

FIG. 11C is the perspective view of the composite permanent magnet design as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). The shape of the magnet (M1, M2 and/or M3) as viewed from the side view is in trapezoid shape, with corners are not equal to 90 degrees. The magnetic charges on the magnet surface, such as S1 and S2 also contribute to the field as measured outside the composite magnet. This approach enables further optimization of the magnetic surface charges to improve magnetic flux or magnetic field distribution that can be utilized by the VCM coil, which improves operation efficiency. In another embodiment, the composite magnet is attached to the soft magnetic yoke (not shown here).

FIG. 11D is the front top view of the composite permanent magnet placed on soft magnetic yoke as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). The shape of the magnet (M1, M2 and/or M3) as viewed from the side view is in trapezoid shape, with corners are not equal to 90 degrees. The magnetic charges on the magnet surface, such as S1 and S2 also contribute to the field as measured outside the composite magnet. This approach enables further optimization of the magnetic surface charges to improve magnetic flux or magnetic field distribution that can be utilized by the VCM coil, which improves operation efficiency.

In another embodiment, the composite magnet is attached to the soft magnetic yoke 139 a. The shape of the cross-section surface S1 and S2 is rectangular shape.

FIG. 11E is the front top view of the composite permanent magnet placed on soft magnetic yoke as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2) and a third magnet (M3). The first magnet (M1) and the third magnet (M3) has the magnetization direction to be opposite to each other. The second magnet (M2) has magnetization direction substantially perpendicular to the magnetization direction of the first magnet (M1) and the third magnet (M3). The shape of the magnet (M1, M2 and/or M3) as viewed from the side view is in trapezoid shape, with corners are not equal to 90 degrees. The magnetic charges on the magnet surface, such as S1 and S2 also contribute to the field as measured outside the composite magnet. This approach enables further optimization of the magnetic surface charges to improve magnetic flux or magnetic field distribution that can be utilized by the VCM coil, which improves operation efficiency.

In another embodiment, the composite magnet is attached to the soft magnetic yoke 139 a. The soft magnetic yoke 139 a may further includes mounting holes 145. The shape of the cross-section surface S1 and S2 is rectangular shape, or can also be in trapezoid shape.

FIG. 12A illustrates a side view of an example structure of a composite permanent magnet as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The dashed arrow shows the magnetization direction within each magnet. N and S represents magnetic north and south pole. The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1), the third magnet (M3) and the fifth magnet (M5) has magnetization direction substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). In addition, the third magnet (M3) has magnetization direction to be opposite with the magnetization direction of the first magnet (M1) and the fifth magnet (M5). M1, M2, M3, M4 and M5 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 12B illustrates an example structure of a composite permanent magnet as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The dashed arrows show the magnetization direction within each magnet. N and S represents magnetic north and south pole. The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1) and the fifth magnet (M5) have magnetization direction with an acute angle with respect to the magnetization direction of the second magnet (M2) and fourth magnet (M4) respectively, as illustrated in FIG. 12B. In addition, the third magnet (M3) has magnetization direction to be substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). M1, M2, M3, M4 and M5 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke 139 a.

FIG. 12C is the front top view of the composite permanent magnet design as described in another embodiment of the invention as illustrated in FIG. 12A. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The arrows show the magnetization direction within each magnet. The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1), the third magnet (M3) and the fifth magnet (M5) has magnetization direction substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). In addition, the third magnet (M3) has magnetization direction to be opposite with the magnetization direction of the first magnet (M1) and the fifth magnet (M5). M1, M2, M3, M4 and M5 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other.

FIG. 12D is the perspective view of the composite permanent magnet design as described in another embodiment of the invention as illustrated in FIG. 12B. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The dashed arrows show the magnetization direction within each magnet. The second magnet (M2) and the fourth magnet (M4) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fourth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1) and the fifth magnet (M5) have magnetization direction with an acute angle with respect to the magnetization direction of the second magnet (M2) and fourth magnet (M4) respectively, as illustrated in FIG. 12B. In addition, the third magnet (M3) has magnetization direction to be substantially perpendicular to the magnetization direction of the second magnet (M2) and fourth magnet (M4). M1, M2, M3, M4 and M5 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke (not shown here).

FIG. 13A is the front top view of the composite permanent magnet design as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet

(M2), a third magnet (M3), a fourth magnet (M4), a fifth magnet (M5) and a sixth magnet (M6). The dashed arrows show the magnetization direction within each magnet. The + and − sign represent magnetic charge polarity. The second magnet (M2) and the fifth magnet (M5) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fifth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1) and the third magnet (M3) have magnetization direction with an acute angle with respect to the magnetization direction of the second magnet (M2). The fourth magnet (M4) and the sixth magnet (M6) have magnetization direction with an acute angle with respect to the magnetization direction of the fifth magnet (M5), as illustrated in FIG. 13A. M1, M2, M3, M4, M5 and M6 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke (not shown here).

FIG. 13B is the perspective view of the composite permanent magnet design as described in another embodiment of the invention. A composite permanent magnet in accordance with the present description includes a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4), a fifth magnet (M5) and a sixth magnet (M6). The dashed arrows shows the magnetization direction within each magnet. The second magnet (M2) and the fifth magnet (M5) has the magnetization direction to be opposite to each other. The second magnet (M2) and the fifth magnet (M4) also have the size and shape to be close to each other. The first magnet (M1) and the third magnet (M3) have magnetization direction with an acute angle with respect to the magnetization direction of the second magnet (M2). The fourth magnet (M4) and the sixth magnet (M6) have magnetization direction with an acute angle with respect to the magnetization direction of the fifth magnet (M5), as illustrated in FIG. 13A. M1, M2, M3, M4, M5 and M6 can be in rectangular shape as seen from the side view, or can be in trapezoid shape as viewed from the side view. Each piece of magnet in the composite magnet are connected to each other. The composite magnet is attached to the soft magnetic yoke (not shown here).

The above figures are examples of the individual composite magnet that can be utilized for VCM, particular for hard disk drive applications. Multiple composite permanent magnets can be utilized with particular periodic pattern and with different cross section shapes to form magnet structures for high efficiency motors and generators to improve power density. The magnet components to form composite magnet may not be all in rectangular shape, in some applications, as stated earlier, have trapezoid shape.

In another embodiment, a hard disk drive where the VCM is operated via a set of VCM magnet. Where at least one VCM magnet includes a composite magnet placed on the soft magnetic yoke. The composite magnet can be in any of the configurations described above.

The following list of aspects reflects a variety of the embodiments explicitly contemplated by the present application. Those of ordinary skill in the art will readily appreciate that the aspects below are neither limiting of the embodiments disclosed herein, nor exhaustive of all of the embodiments conceivable from the disclosure above, but are instead meant to be exemplary in nature.

1. A composite permanent magnet comprises a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). The M1, M2, M3, M4 and M5 are deposited or assembled together and next to each other. The volume of M2 and M4 are higher than the volume of M1, M3 and M5. The direction of the saturation magnetization of M2 and M4 are opposite to each other. The direction of the saturation magnetization of M1 and M5 is substantially antiparallel to the direction of the saturation magnetization of M3. The direction of saturation magnetization of M1, M3 and M5 is substantially perpendicular to the saturation magnetization of M2 and M4.

2. The composite permanent magnet as in aspect 1, wherein the width of M1, M3 and M5 are approximately the same.

3. The composite permanent magnet as in aspect 1, wherein the width of M2 and M4 are approximately the same.

4. The composite permanent magnet as in aspect 1, wherein the width of M1, M3 and M5 is smaller than the width of M2 and M4.

5. The composite permanent magnet as in aspect 1, wherein the length of M1, M2, M3, M4 and M5 are approximately the same.

6. The composite permanent magnet as in aspect 1, wherein the height of M1, M2, M3, M4 and M5 are approximately the same.

7. The composite permanent magnet as in aspect 1, wherein the materials of M1, M2, M3, M4 and M4 are selected from a ferrite (such as Barium-Iron-Oxygen (Ba—Fe—O), Barium-Nickel-Iron-Oxygen (Ba—Ni—Fe—O), Barium-Strontium-Nickel-Iron-Oxygen (Ba—Sr—Ni—Fe—O), etc.), alnico (such as Aluminum-Nickel-Cobalt (Al—Ni—Co), Aluminum-Nickel-Cobalt-Iron (Al—Ni—Co—Fe), Aluminum-Nickel-Cobalt-Iron-Copper (Al—Ni—Co—Fe—Cu), etc.), rare earth-transition metal-based permanent magnetic materials X-Y or X-Y-Z (where X includes rare-earth elements and their combinations, such as Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Neodymium-Dysprosium (NdDy), Neodymium-Dysprosium-Terbium (NdDyTb), Neodymium-Dysprosium-Terbium-Gadolinium (NdDy TbGd), etc.; Y includes transition metal elements and/or their combinations, such as Iron (Fe), Cobalt (Co), Manganese (Mn), Nickel (Ni), Iron-Cobalt (FeCo), Iron-Cobalt-Nickel (FeCoNi), Iron-Cobalt-Nickel-Manganese (FeCoNiMn), etc.; and Z includes non-metal elements and/or other doping elements and their combinations, such as Boron (B), Silicon (Si), Carbon (C), Nitrogen (N), Copper (Cu), Silver (Ag), Zirconium (Zr), etc.), Mn-based permanent magnetic materials X-Y or X-Y-Z (where X includes Mn, Fe, Manganese-Iron (MnFe), etc.; and Y includes Bismuth (Bi), Al, Gallium (Ga), and/or other doping elements such as Praseodymium (Pr), as well as the combination of these elements), transition metal-platinum-based magnetic material X-Y (where X includes transition metal elements and/or their combinations, such as Fe, Co, FeCo, etc.; and Y includes Platinum (Pt), Rhodium (Rh), Palladium (Pd), Zr, and/or their combinations with/without other doping elements), or Iron-Nitride (Fe—N). Specifically, each of the magnets can be Neodymium-Iron-Boron (NdFeB) based materials with different percentage of Neodymium (Nd) concentration.

8. The composite permanent magnet as in aspect 1, wherein the width of M1, M3 and M5 is ⅓ of the width of M2 and M4, the length of each of the magnet is approximately equal to each other and the height of each of the magnet is approximately equal to each other.

9. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 materials are based on same materials selected from aspect 7.

10. The composite permanent magnet as in aspect 1, wherein M1, M3 and M5 are based on same material selected from aspect 7; M2 and M4 are based on the same material selected from aspect 7; wherein M2 and M4 material is different from M1, M3 and M5 material.

11. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 materials are based on Neodymium-Iron-Boron (NdFeB) materials.

12. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 materials are based on Neodymium-Iron-Boron (NdFeB) materials; M1, M3 and M5 has different percentage of Neodymium (Nd) concentration as compared to M2 and M4.

13. The composite permanent magnet as in aspect 1, wherein the shape of M1, M2, M3, M4 and M5 is in cuboid or rectangular prism.

14. The composite permanent magnet as in aspect 1, wherein the surface of M1, M2, M3, M4 and M5 matches to each other in such a way they can be bonded, glued or pressed together into one composite magnet.

15. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 are glued, pressed, bonded or using other methods to connect together.

16. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 have smooth surface.

17. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 have curved or rough surface, can be joint at the interface when pressed together.

18. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 can be in rectangular shape from front view.

19. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 can be in rectangular shape from side view.

20. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 can be in trapezoid shape from front view.

21. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 can be in trapezoid shape from side view.

22. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 are bonded together and placed on a soft magnetic yoke.

22. The composite permanent magnet as in aspect 1, wherein M1, M2, M3, M4 and M5 are bonded together and placed on a soft magnetic yoke. The said yoke has predrilled mounting holes.

23. A composite permanent magnet comprises a first magnet (M1), a second magnet (M2) and a third magnet (M3). The M1, M2 and M3 are deposited or assembled together and next to each other. The direction of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 is substantially perpendicular to the direction of saturation magnetization of M1 and M3.

24. The composite permanent magnet as in aspect 23, wherein the width of the M1 and M3 are approximately same.

25. The composite permanent magnet as in aspect 23, wherein the width and the volume of M2 is smaller than the width of M1 and M3.

26. The composite permanent magnet as in aspect 23, wherein the length of M1, M2 and M3 are approximately the same.

27. The composite permanent magnet as in aspect 23, wherein the height of M1, M2 and M3 are approximately the same.

28. The composite permanent magnet as in aspect 23, wherein the materials of M1, M2 and M3 are selected from a ferrite (such as Barium-Iron-Oxygen (Ba—Fe—O), Barium-Nickel-Iron-Oxygen (Ba—Ni—Fe—O), Barium-Strontium-Nickel-Iron-Oxygen (Ba—Sr—Ni—Fe—O), etc.), alnico (such as Aluminum-Nickel-Cobalt (Al—Ni—Co), Aluminum-Nickel-Cobalt-Iron (Al—Ni—Co—Fe), Aluminum-Nickel-Cobalt-Iron-Copper (Al—Ni—Co—Fe—Cu), etc.), rare earth-transition metal-based permanent magnetic materials X-Y or X-Y-Z (where X includes rare-earth elements and their combinations, such as Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Neodymium-Dysprosium (NdDy), Neodymium-Dysprosium-Terbium (NdDyTb), Neodymium-Dysprosium-Terbium-Gadolinium (NdDy TbGd), etc.; Y includes transition metal elements and/or their combinations, such as Iron (Fe), Cobalt (Co), Manganese (Mn), Nickel (Ni), Iron-Cobalt (FeCo), Iron-Cobalt-Nickel (FeCoNi), Iron-Cobalt-Nickel-Manganese (FeCoNiMn), etc.; and Z includes non-metal elements and/or other doping elements and their combinations, such as Boron (B), Silicon (Si), Carbon (C), Nitrogen (N), Copper (Cu), Silver (Ag), Zirconium (Zr), etc.), Mn-based permanent magnetic materials X-Y or X-Y-Z (where X includes Mn, Fe, Manganese-Iron (MnFe), etc.; and Y includes Bismuth (Bi), Al, Gallium (Ga), and/or other doping elements such as Praseodymium (Pr), as well as the combination of these elements), transition metal-platinum-based magnetic material X-Y (where X includes transition metal elements and/or their combinations, such as Fe, Co, FeCo, etc.; and Y includes Platinum (Pt), Rhodium (Rh), Palladium (Pd), Zr, and/or their combinations with/without other doping elements), or Iron-Nitride (Fe—N). Specifically, each of the magnets can be Neodymium-Iron-Boron (NdFeB) based materials with different percentage of Neodymium (Nd) concentration.

29. The composite permanent magnet as in aspect 23, wherein the width of M2 is ⅓ of the width of M1 and M3, the length of M1, M2 and M3 are approximately equal to each other and the height of M1, M2 and M3 are approximately equal to each other.

30. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 are based on same materials selected from aspect 28.

31. The composite permanent magnet as in aspect 23, wherein M1 and M3 are based on same material selected from aspect 28, M2 is based on another material selected from aspect 28.

32. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 materials are based on Neodymium-Iron-Boron (NdFeB) materials.

33. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 materials are based on Neodymium-Iron-Boron (NdFeB) materials with different percentage of Neodymium (Nd) concentration.

34. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 are glued, bonded, pressed or joint together.

35. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 have curved or rough surface, can be joint at the interface when pressed together.

36. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 can be in rectangular shape from front view.

37. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 can be in rectangular shape from side view.

38. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 can be in trapezoid shape from front view.

39. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 can be in trapezoid shape from side view.

40. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 are bonded together and placed on a soft magnetic yoke.

41. The composite permanent magnet as in aspect 23, wherein M1, M2 and M3 are bonded together and placed on a soft magnetic yoke. The said yoke has predrilled mounting holes.

42. The composite permanent magnet as in aspect 23, wherein further includes metallic or metallic alloy coating such as Ni, NiFe, or other materials coating on the surface of the composite magnet.

43. The composite permanent magnet as in aspect 23, wherein the magnetization direction of M1 and M3 are opposite to each other, and along the height of the magnet direction. The magnetization direction of M2 is perpendicular to the magnetization direction of M1 and M3, along the width of the composite magnet.

44. A composite permanent magnet comprises a first magnet (M1), a second magnet (M2), a third magnet (M3) and a fourth magnet (M4). The M1, M2, M3 and M4 are deposited or assembled together and next to each other. The direction of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 and M4 are opposite to each other. The direction of the saturation magnetization of M2 and M4 are substantially perpendicular to the direction of the saturation magnetization of M1 and M3.

45. The composite permanent magnet as in aspect 44, wherein the width of the M1 and M3 are approximately same.

46. The composite permanent magnet as in aspect 44, wherein the width and the volume of the M2 and M4 is smaller than M1 and M3.

47. The composite permanent magnet as in aspect 44, wherein the length of the M1, M2, M3 and M4 are approximately the same.

48. The composite permanent magnet as in aspect 44, wherein the height of M1, M2, M3 and M4 are approximately the same.

49. The composite permanent magnet as in aspect 44, wherein the materials of M1, M2, M3 and M4 are selected from a ferrite (such as Barium-Iron-Oxygen (Ba—Fe—O), Barium-Nickel-Iron-Oxygen (Ba—Ni—Fe—O), Barium-Strontium-Nickel-Iron-Oxygen (Ba—Sr—Ni—Fe—O), etc.), alnico (such as Aluminum-Nickel-Cobalt (Al—Ni—Co), Aluminum-Nickel-Cobalt-Iron (Al—Ni—Co—Fe), Aluminum-Nickel-Cobalt-Iron-Copper (Al—Ni—Co—Fe—Cu), etc.), rare earth-transition metal-based permanent magnetic materials X-Y or X-Y-Z (where X includes rare-earth elements and their combinations, such as Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Neodymium-Dysprosium (NdDy), Neodymium-Dysprosium-Terbium (NdDyTb), Neodymium-Dysprosium-Terbium-Gadolinium (NdDy TbGd), etc.; Y includes transition metal elements and/or their combinations, such as Iron (Fe), Cobalt (Co), Manganese (Mn), Nickel (Ni), Iron-Cobalt (FeCo), Iron-Cobalt-Nickel (FeCoNi), Iron-Cobalt-Nickel-Manganese (FeCoNiMn), etc.; and Z includes non-metal elements and/or other doping elements and their combinations, such as Boron (B), Silicon (Si), Carbon (C), Nitrogen (N), Copper (Cu), Silver (Ag), Zirconium (Zr), etc.), Mn-based permanent magnetic materials X-Y or X-Y-Z (where X includes Mn, Fe, Manganese-Iron (MnFe), etc.; and Y includes Bismuth (Bi), Al, Gallium (Ga), and/or other doping elements such as Praseodymium (Pr), as well as the combination of these elements), transition metal-platinum-based magnetic material X-Y (where X includes transition metal elements and/or their combinations, such as Fe, Co, FeCo, etc.; and Y includes Platinum (Pt), Rhodium (Rh), Palladium (Pd), Zr, and/or their combinations with/without other doping elements), or Iron-Nitride (Fe—N). Specifically, each of the magnets can be Neodymium-Iron-Boron (NdFeB) based materials with different percentage of Neodymium (Nd) concentration.

50. The composite permanent magnet as in aspect 44, wherein the width of M2 and M4 is ⅓ of the width of M1 and M3, the length of each of the magnets is approximately equal to each other and the height of each of the magnets is approximately equal to each other.

51. The composite permanent magnet as in aspect 44, wherein M1, M2, M3 and M4 are based on the same material selected from aspect 49.

52. The composite permanent magnet as in aspect 44, wherein M1 and M3 are based on same material selected from aspect 49, M2 is based on another material selected from aspect 49.

53. The composite permanent magnet as in aspect 44, wherein M1, M2, M3 and M4 materials are based on Neodymium-Iron-Boron (NdFeB) materials.

54. The composite permanent magnet as in aspect 44, wherein M1, M2, M3 and M4 materials are based on Neodymium-Iron-Boron (NdFeB) materials with different percentage of Neodymium (Nd) concentration.

55. The composite permanent magnet as in aspect 44, wherein M1, M2, M3 and M4 are glued, bonded, pressed or joint together.

56. The composite permanent magnet as in aspect 44, wherein further includes metallic or metallic alloy coating such as Ni, NiFe, or other materials coating on the surface of the composite magnet.

57. The composite permanent magnet as in aspect 44, wherein the magnetization direction of M1 and M3 are opposite to each other, and along the height of the magnet. The magnetization direction of M2 and M4 are perpendicular to the magnetization direction of M1 and M3, along the width of the composite magnet.

58. A hard disk drive includes two VCM magnets, where at least one of the VCM magnets includes a composite magnet, where at least three or more pieces of magnets are glued or bond together. Where two of the magnets have the saturation magnetization direction to be in opposite direction. At least one of the magnets have the saturation magnetization direction to be perpendicular to the other two magnets.

59. The hard disk drive as in aspect 58, wherein the composite magnet is placed on the soft magnetic yoke.

60. The hard disk drive as in aspect 59, wherein the soft magnetic yoke has predrilled mounting holes.

61. The hard disk drive as in aspect 58, wherein the VCM magnet has metallic coating, such as Ni plated coat.

62. A composite magnet system includes multiple magnets connect to each other or to a magnet holder, where each of the magnet is comprise of composite magnet structure in aspect 1.

63. A composite magnet system includes multiple magnets connect to each other or to a magnet holder, where each of the magnet is comprise of composite magnet structure in aspect 23.

64. A composite magnet system includes multiple magnets connect to each other or to a magnet holder, where each of the magnet is comprise of composite magnet structure in aspect 44.

The embodiments were chosen and described to best explain the principles of the invention and its practical application to persons who are skilled in the art. As various modifications, could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. Modifications and variations may be made to the disclosed embodiments while remaining within the spirit and scope of the method, system and apparatus. The implementations described above and other implementations are within the scope of the following claims. 

1. A hard disk drive includes composite magnet as voice coil motor magnet, where a composite permanent magnet comprising: a first magnet (M1), a second magnet (M2) and a third magnet (M3). M1, M2 and M3 are deposited, bonded, glued or assembled together and next to each other. The directions of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 is substantially perpendicular to the direction of saturation magnetization of M1 and M3.
 2. The composite permanent magnet of claim 1, wherein the width of M1 and M3 are approximately the same.
 3. The composite permanent magnet of claim 1, wherein the width of M2 is smaller than the width of M1 and M3.
 4. The composite permanent magnet of claim 1, wherein the magnet further placed on a soft magnetic yoke.
 5. The composite permanent magnet of claim 1, wherein the shape of M1, M2 and M3 in trapezoid shape as seen in front view or side view.
 6. The composite permanent magnet of claim 1, wherein the height of M1, M2 and M3 are approximately the same.
 7. The composite permanent magnet of claim 1, wherein: M1, M2 and M3 materials is at least one of: alnico, ferrite, a rare earth-transition metal-based permanent magnetic material, a manganese-based permanent magnetic material, a transition metal-platinum-based magnetic material, or Iron-Nitride (Fe—N), a neodymium-based permanent magnetic material, such as neodymium-iron-boron.
 8. The composite permanent magnet of claim 1, wherein M1, M2 and M3 materials are same.
 9. The permanent magnet of claim 1, wherein M1, M2 and M3 are attached to each other via at least one of: injection molding, compression molding, adhesion, high pressure compression, high pressure annealing, sintering, gluing or direct bonding.
 10. A composite permanent magnet comprises a first magnet (M1), a second magnet (M2), a third magnet (M3) and a fourth magnet (M4). M1, M2, M3 and M4 are deposited or assembled together and next to each other. The direction of the saturation magnetization of M1 and M3 are opposite to each other. The direction of the saturation magnetization of M2 and M4 are opposite to each other. The direction of the saturation magnetization of M2 and M4 are substantially perpendicular to the direction of the saturation magnetization of M1 and M3.
 11. The composite permanent magnet of claim 10, wherein: M1, M2, M3 and M4 materials is at least one of: alnico, ferrite, a rare earth-transition metal-based permanent magnetic material, a manganese-based permanent magnetic material, a transition metal-platinum-based magnetic material, or Iron-Nitride (Fe—N), a neodymium-based permanent magnetic materials, such as neodymium-iron-boron.
 12. The composite permanent magnet of claim 10, wherein M1 and M3 materials are the same.
 13. The composite permanent magnet of claim 10, wherein M1, M2, M3 and M4 are attached to each other via at least one of: injection molding, compression molding, adhesion, high pressure compression, high pressure annealing, sintering, gluing or direct bonding.
 14. The composite permanent magnet of claim 10, wherein further includes other magnet pieces with periodic structure of claim
 10. 15. A hard disk drive includes composite magnet as voice coil motor magnet, where a composite permanent magnet comprising: a first magnet (M1), a second magnet (M2), a third magnet (M3), a fourth magnet (M4) and a fifth magnet (M5). M1, M2, M3, M4 and M5 are deposited or assembled together and next to each other. The directions of the saturation magnetization of M2 and M4 are opposite to each other. The direction of the saturation magnetization of M1 and M5 is substantially antiparallel to the direction of the saturation magnetization of M3. The directions of saturation magnetization of M1, M3 and M5 are substantially perpendicular to the direction of saturation magnetization of M2 and M4.
 16. The composite permanent magnet of claim 15, wherein: M1, M2, M3, M4 and M5 materials is at least one of: alnico, ferrite, a rare earth-transition metal-based permanent magnetic material, a manganese-based permanent magnetic material, a transition metal-platinum-based magnetic material, or Iron-Nitride (Fe—N), a neodymium-based permanent magnetic materials, such as neodymium-iron-boron.
 17. The composite permanent magnet of claim 15, wherein the magnet further placed on a soft magnetic yoke.
 18. The composite permanent magnet of claim 15, wherein the shape of M1, M2, M3, M4 or M5 can be in trapezoid or other none rectangular shape as seen from front or side view.
 19. The composite permanent magnet of claim 15, wherein the volume of M2 and M4 are higher than the volume of M1, M3 and M5 respectively.
 20. The composite permanent magnet of claim 15, wherein M1, M2, M3, M4 and M5 are attached to each other via at least one of: injection molding, compression molding, adhesion, high pressure compression, high pressure annealing, sintering, gluing or direct bonding. 